Although evidence suggests that promotion of children's behavioral and socioemotional competence is an effective strategy to prevent mental, emotional and behavioral disorders in adulthood, identifying evidence-based interventions that promote child competencies, constitutes a challenge. Based on anecdotal evidence, equine assisted counseling has shown promise, but unfortunately, little experimental research has been done to determine its causal effects. Although important, prior studies on equine assisted interventions are limited by their focus on case studies, small sample sizes and correlational designs. We are thus unable to make causal inferences about the efficacy of equine assisted interventions. Moreover, our knowledge of the causal pathways underlying the effects of equine assisted interventions is extremely limited. Without this knowledge, we cannot ascertain whether - and how- equine assisted intervention provides an effective approach to enhance socioemotional and behavioral strengths of individual children to facilitate the prevention or resolution of mental, emotional and behavioral problems. The objective of this study is to conduct a randomized experimental trial to determine the efficacy of PATH to success - an existing equine assisted intervention - in improving the behavioral and socioemotional competence of elementary and middle-school age children. In addition to measuring its effects on socioemotional and behavioral competence, this study will measure children's physiological markers of stress-system activity - salivary cortisol levels - to determine whether effects of equine assisted intervention can be explained by changes in activity of the Hypothalamic Pituitary Adrenal (HPA) Axis, one of the bodies'main systems regulating physiological and behavioral responses to psychological stress. We will select 128 5th through 8th grade children based on their social and behavioral competence and referral, and randomly assign them to a treatment or waitlisted condition. Teachers, parents, children and trained observers will rate child competence in various domains at multiple time-points, during which child salivary cortisol will be collected. This study will first determine whether PATH to Success improves children's socioemotional and behavioral competence. Second, it will determine effects on physiological indicators of child stress, and the extent to which they explain improvements in socioemotional and behavioral competence. Last, we will gain knowledge about the dosage effects and possible longer-term effects, about which virtually nothing is known. The results of the proposed study are expected to have an important positive impact on our understanding of the effects of equine assisted intervention on child socioemotional and behavioral competence and stress, and on the broader field of mental health professionals interested in expanding innovative, evidence- based approaches. PUBLIC HEALTH RELEVANCE: This proposed research increases our knowledge about the effects of equine assisted intervention on children's behavioral and socioemotional competence, and the physiological pathways underlying these effects. The proposed study focuses on an important yet under-investigated area of human animal interaction and child development that has potential applicability to the prevention or resolution of social, emotional, academic and behavioral problems of children and youth.